depends on your size, if you trade about 100 shares or less then yes it is, if you primarily use limit orders and wait to get hit, then yes it is cheaper as well, there is no harm in trying it out for a few days, it takes 24 to 48 hours to initiate, and you can see your exact commission cost in the TWS trade log, if it ends up being more expensive then you can easily switch back.

Do it and find out, i regret not doing it earlier as i'm paying about 30% less on average now.

depends on your size, if you trade about 100 shares or less then yes it is, if you primarily use limit orders and wait to get hit, then yes it is cheaper as well, there is no harm in trying it out for a few days, it takes 24 to 48 hours to initiate, and you can see your exact commission cost in the TWS trade log, if it ends up being more expensive then you can easily switch back.

Do it and find out, i regret not doing it earlier as i'm paying about 30% less on average now.

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Do the math for your market. For the TSX, in Canada, it's 15% more expensive for the first 300,000 shares each month.